Azo dye



Patented Feb. 24, 1942 AZO on Francis 11. Smith, woodman, N. 1.,

E. I. du Pont de Nemours &

mington, Del.,

asslgnor to Company, Wilcorporation of Delaware No Drawing. Application March as, 1940,

. Serial 'No. 326,005

2 Claims. cl. 8-24) This invention relates to dyeing and to new dyestufl compositions. In the dyeing of so-called union goods, which consist in general of cloth containing mixed fibers with diiferent dyeing properties, where colored effects are desired, a

useful process involves the dyeing of one of the fibers with a dye which is not substantive to the other fiber and thereafter dyeing the second fiber with a dye which is not substantive to the first. This process is imperfect, however, particularly as applied to azo dyes in that some azo dyes, which are substantive to cotton, and are substantially non-substantive to cellulose acetate, stain the cellulose acetate fibers sufliciently to produce imperfect results. For example, if a cloth is composed of a mixture of cotton and cellulose acetate threads, it may be desired to dye the cotton brown and the cellulose acetate scarlet. However, if the brown stains the cellulose acetate, the scarlet produced will be muddy and the effect imperfect. The trade has developed this process of dyeing to the point where a large number of colors are known which are highly substantive to one or the other of the fibers but have little affinity for the other. Nevertheless, this imperfection still remains.

j It is an object of this y colors having high afiinity for one of these fibers and low afilnity for the other.

object of the invention is to improve the dyeing properties for this purpose of those colors which are substantive to cotton but which stain cellulose acetate.

invention to improve A more specific;-

approximately 16 hours. A piece of cloth was dyed with the composition. A piece of the same cloth was dyed with the same strength of the It has been proposed to use highly porous solid adsorbents, such as activated carbon, to decrease the acetate silk staining impurities of azo dyestuffs which are used in the indicated process. Heretofore, the activated carbon had been added to the dyestuff solution, allowed to remain there long enough to decrease the acetate staining impurities of the dye, and removed therefrom by filtration prior to the isolation of the dye. In the prior art the activated carbon was always added to, and removed from, the dye bath by processes involving filtration, clarification and sometimes reworking.

The objects of this invention are accomplished, generally speaking, by preparing the dye, activated carbon therewith and isolating the dye and the carbon without separating them. We

have found that direct and developed dyestufl's can be considerably improved with regard. to cel lulose acetate staining qualities by this process.

The following examples, which are not intended as a limitation, illustrate the invention.

. Example 1 Approximately 10 grams of Color Index- No. 581 was milled with 0.6 gram of activated carbon for same dye not containing activated carbon. The

, dyeing effect on the cotton threads of the cloth was not less but the dyeing effect of the dyestufl on the cellulose acetate was markedly less in the case of the color containing the carbon.

The experiment was repeated in connection with the following colors using a variety of concentrations both of carbon and of dyestuff. Results uniformly showed a decrease in the acetate. staining properties of the colors.

. TABLE I Product Colon Index N o. 581.

Co or dexNo. 682.

. Color Index No. 267.

Color Index N o. 593.

Color Index N o. 594.

Color Index N o. 502.

Color Index No. 612.

Color Index No. 464.

Color Index N o. 387.

Color Index No. 561.

Color Index No. 561.

H acid (para-phenylene'diamine);

(metaghenylene-diamme) Aminoacid meta-tolu1dme 1,6- Oleves meta-toluidineara-amino-benzoyl (developed with beta-naphtliolf.

Phenol be meta-phenylene-diamine gamma acid.

Amino-G acid toluidine pam-amino-benzoyl-benzoylated.

Cloves para-phenylene-diamme 8 acid para-phenylene-diamine.

Para-chloro-emhne H acid benzi- XIX Lil-Cloves acid H acid benzidine mixed Clevesacid.

XX Aniline H acid benzidine mixed Cloves acid.

XXI Pam-chloroaniline -v Hacid benzidine v meta-phenylene-diamine.

XXII Para-nitro-aniline Hacid benzldine meta-phenylene-dlamine.

XXIII Ortho-chloro-para-nitro-aniline I H acid benzidine -v meta-phenylene-dramine.

XXIV Aniline Hacid benzdme alpha-naphthylamine.

XXV (Ortho-amino-phenol-para-sulfonic acid resorclnol; coppered) benzidme salicylic acid.

XXVI 'Dioxy-S acid toluidiue gamma acid dioxy-S acid.

XXVII Na hthionic acid 2R acid -v metap enylene-diamine benzidine o salicylic acid.

XXVIII Dehydrothio-para-toluylene-sulfomc acid -o resorcln anilme.-

XXIX Acetylamino-Cleves me ta-to luidme -e meta-toluidine salleyllcacid.

XXX Salicylic acid zidine resorcin naphthionic acid.

XXXI Naphthionic acid meta-toluylene-diamine meta-toluylene-diamine.

XXXII Amino-salicylic acid alpha-naphthylamine gammaacid.

XXXIIL Meta-toluylene-diamine 4- gamma acid pera-phenylene diamlne Clevesacid. XXXIV Cresidine eamino-Cloves acid 1,7-

Cleves acid 1,

hydroxy acid (developed with beta-naphthol).

meta-toluidme meta- Example XXXV A 0.1 gram mole charge of Color Index No. 581 was prepared in the customary manner. After the final coupling to meta-phenylene-diamine was complete, 2.0 grams of activated carbon was added. The suspension was heated with stirring to 80-85 C. for approximately 20 minutes. The suspension was salted with sodium chloride to a clear rim, filtered and dried. The product stained cotton as well or better and cellulose acetate noticeably less than a product prepared in a similar manner except omitting the addition of activated carbon.

Example XXXVI Benzidine sulfate paste equivalent to 9.2 parts of pure benzidine was tetrazotized in the usual manner and coupled in strong mineral acidity with H acid paste equivalent to 16.25 parts of pure mono-sodium salt of l-amino-B-naphthol- 3,6- disulfonic acid. After stirring overnight at room temperature, the temperature was lowered to C., the acidity was reduced with an aqueous solution of 5.25 parts of soda ash, and 1 part of activated carbon Was added. Benzene diazonium chloride solution, made in the customary manner from 5.36 parts of aniline, was added, and then an aqueous solution of 12.9 parts of soda ash and 1 part of activated carbon were added immediately. After one-half hour, the temperature was 19 C. One part of activated carbon was added. Then 0.813 part of meta-phenylene-diamin was added in the form of an aqueous solution. The mixture was allowed to stir ten minutes before the addition of 1 part of activated carbon. Five minutes later 4.83 parts of meta-phenylene-diamine in the form of an aqueous solution was added. One part of activated carbon was added immediately thereafter. The reaction mixture was allowed to stir for one hour, and then 1 part of activated carbon was added. The dyestufi was salted, isolated, and dried in the customary manner. The trisazo dyestulf thus synthesized was a direct black which stained acetate silk considerably less than the identical dye lacking the activated carbon.

The usual commercially available types of activated carbon are useful; for example: Norit A, Nuchar, Colloidal Black Dispersion B, Colloidal Black Dispersion O, Colloidal Black Dispersion M, Darco G450, and Aquoid -R-X. No definite amount of these products was required, varying amounts being-satisfactory in every case.

The activated carbon may be added at any convenient stage during the process of preparation of the dyestufi, but is not to be removed from the dyestufi'.

The herein-described invention has a distinct advantage over known methods of improving the cellulose acetate staining properties of direct and developed colors. No additional filtrations, clariflcations and reworking procedures are necessary to obtain the desired effect, as is the case with methods disclosed in the prior art.

As many apparently widely difierent embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. The process of dyeing union textiles containing cellulose acetate fibers without imparting substantial stain to the acetate, and with the production of color having good discharge properties, which comprises applying a composition containing a direct cotton azo dye, activated carbon, and water to the said textiles.

2. The process of dyeing union textiles containing cellulose acetate fibers without imparting substantial stain to the acetate, and with the production of color having good discharge properties, which comprises applying a composition containing the compound represented by the formula: aniline- H-acid -benzidine meta-phenylene di amine, activated carbon, and water to the said textiles.

a FRANCIS H. SMITH. 

